From a botanical standpoint, dormancy is not a sign of a plant dying but a sophisticated survival strategy. For a Jasmine plant (primarily referring to common varieties like Jasminum officinale or Jasminum nudiflorum), winter presents a significant challenge: shorter day lengths, reduced light intensity, and colder temperatures. These environmental cues signal the plant to slow down its metabolic processes dramatically. Photosynthesis, transpiration, and cell division occur at a minimal rate to conserve energy. The plant essentially enters a state of rest, redirecting resources to its core structures—the roots and main stems—to survive the unfavorable conditions and prepare for vigorous growth in the spring.
The answer depends significantly on your climate and the specific type of jasmine. True or Common Jasmine (Jasminum officinale) is deciduous in temperate climates. When exposed to a consistent period of cold weather, it will drop its leaves and enter a full dormancy. Its stems remain alive but bare. Conversely, in frost-free climates, it may remain evergreen and continue to grow, albeit more slowly. Winter Jasmine (Jasminum nudiflorum) is also deciduous and expects a dormant period. However, many popular "jasmine" plants, like Star Jasmine (Trachelospermum jasminoides), are evergreen vines. They are not truly deciduous but will still experience a period of winter quiescence—a drastic slowdown in growth without complete leaf loss, especially if grown in their recommended hardiness zones.
Providing the correct care during this dormant phase is crucial for the plant's health and its performance in the coming season. The primary goals are protection and restraint.
Outdoor hardy jasmine varieties can withstand winter chill but may need protection from harsh, freezing winds. Planting them in a sheltered location is ideal. For jasmine grown in containers, the roots are far more vulnerable to freezing than those in the ground. It is often necessary to move potted plants to a sheltered spot like an unheated garage, shed, or cool greenhouse where temperatures stay above freezing. Avoid bringing hardy dormant jasmine into a warm living area, as the heat will disrupt its natural cycle and force weak, etiolated growth.
Watering needs diminish drastically during dormancy. The plant is not actively growing and will not uptake water quickly. Overwatering is the single greatest threat during winter, as cold, soggy soil will lead to root rot. Allow the soil to dry out much more thoroughly between waterings. For outdoor plants, natural precipitation is often sufficient unless there is a prolonged dry spell. Fertilization must be completely halted in late summer or early fall. Feeding a dormant plant can force new, tender growth that is highly susceptible to cold damage and will waste the plant's stored energy.
While major pruning is best done after flowering or in early spring, winter is a good time for light maintenance and inspection. You can remove any dead, damaged, or diseased branches. The leafless structure of deciduous types also makes it easier to see and shape the plant's framework. Even while dormant, the plant benefits from receiving natural light, so ensure potted plants in storage are not kept in complete darkness for extended periods.
